Abstract
BACKGROUND: Older adults are at higher risk of severe outcomes from COVID-19 with comorbidities increasing such risk. Much less is known about the outcomes of young adults with COVID-19 despite their having had high infection rates. OBJECTIVES: Our objective was to determine outcomes of hospitalized young adults with COVID-19 infection including rates of oxygen use, mortality, ICU admission, intubation, duration of hospitalization, and factors associated with adverse outcomes. STUDY DESIGN: This retrospective cohort study included EHR data from 21 health systems in the United States on 18-29-year-olds hospitalized with COVID-19 from March 1, 2020 - January 31, 2022. Oxygen need was used to identify symptomatic COVID-19. Rates for mortality, ICU admission, and intubation were calculated for the symptomatic and asymptomatic groups. Effects of demographic and health characteristics on outcomes were assessed as were changes in hospital outcomes over time. RESULTS: Our sample included 9871 young adults hospitalized with COVID-19; 35% required oxygen. Of those who required oxygen, 53.5% were female, 23.7% had an anxiety disorder, 2.6% died (n = 89), 27.7% were admitted to the ICU (n = 955), and 15.8% were intubated (n = 547). A past-year history of any cancer was associated with a 2.1 times increased odds of death. Vaccination was associated with a >40% reduction in the odds of ICU admission. Mortality rates did not change significantly across the study period. CONCLUSIONS: COVID-19 caused significant morbidity and mortality in hospitalized young adults who required oxygen. A cancer history was associated with increased risk of death. Vaccination appeared to have had a protective effect on illness severity.